Power efficient scheme for self localization in wireless sensor networks

With the tremendous applications of the wireless sensor network, self-localization has become one of the challenging subject matter that has gained attention of many researchers in the field of wireless sensor network. Localization is the process of assigning or computing the location of the sensor nodes in a sensor network. As the sensor nodes are deployed randomly, we do not have any knowledge about their location in advance. As a result, this becomes very important that they localize themselves as manual deployment of sensor node is not feasible. Also, in WSN the main problem is the power as the sensor nodes have very limited power source. This paper provides a novel solution for localizing the sensor nodes using controlled power of the beacon nodes such that we will have longer life of the beacon nodes which plays a vital role in the process of localization as it is the only special nodes that has the information about its location when they are deployed such that the remaining ordinary nodes can localize themselves in accordance with these beacon node. We develop a novel model that first finds the distance of the sensor nodes then it finds the location of the unknown sensor nodes in power efficient manner. Our simulation results show the effectiveness of the proposed methodology in terms of controlled and reduced power.     

Rice-like CuO nanostructures for sensitive electrochemical sensing of hydrazine

In this work, a low temperature aqueous chemical growth methodology was used for the fabrication of CuO nanostructures. The as-synthesised nanostructures were then elaborately characterised by number of analytical techniques such as scanning electron microscopy (SEM) and X-ray powder diffraction (XRD). The obtained nanostructures were observed to possess interlaced rice-shaped structural features with the length and width of individual rice determined to be in the range of 200–300 nm and 50–100 nm respectively. The unique nanostructures when utilised as electrode material exhibited excellent electro-catalytic potential towards oxidation of hydrazine in alkaline media. The excellent conductive of CuO added by the high surface area of obtained nanorice-like structures enabled development of highly sensitive (3087 µA mM⁻¹ cm⁻²), selective and stable electrochemical sensor for hydrazine. In addition, the successfully application of the developed sensor in spiked tap, bottled and industrial water samples for the detection of hydrazine suggested its feasibility for practical environmental application.

     

Structural characterization of octadecyl modified MCM-41 silica by NMR and FTIR

Mesoporous MCM-41 silica spheres were prepared via the pseudomorphic route, using commercial prontosil silica spheres. Surface modification offers a great opportunity to adjust both the pore structure and surface properties of MCM-41 type materials which results in materials of improved hydrothermal and mechanical stability to make them promising candidates for chromatographic applications. In the present context, the obtained MCM-41 silica spheres were surface modified with octadecyl (C₁₈) alkyl chains, by using direct grafting and surface polymerization methods, in order to vary the degree of surface hydrophobicity. The resulting materials were characterized before and after surface modification using various characterization techniques, with special emphasis on NMR and FTIR spectroscopies, for studying the attachment, mobility and the conformational order of the attached alkyl chains.     

Water‐Resistant Poly(vinyl alcohol)‐Silica Hybrids through Sol‐Gel Processing

Poly(vinyl alcohol) (PVA)‐silica hybrids with exceptionally reduced solubility in water were synthesized. The hybrid xerogels were fabricated through sol‐gel processing of a mixture of PVA and the acid‐catalyzed silica precursor tetraethoxysilane. The effects of varying ratios of PVA and silica precursor on the surface structure, thermal properties, crystallinity, and solubility of the hybrids were investigated. Unlike the highly water‐soluble nature of PVA, all the hybrids displayed considerably reduced solubility in water. This anomalous behavior of PVA in the hybrids can be attributed to the unavailability of its pendant –OH groups. Water‐resistant PVA‐silica hybrids can find applications in various technologies requiring biocompatible systems that are stable in aqueous environments.     

Accident under-reporting among employees: Testing the moderating influence of psychological safety climate and supervisor enforcement of safety practices

We examined accident under-reporting with data from 425 employees employed in 5 industries with above average risk for employee injuries. We expected that rates for unreported accidents would be higher than rates for reported accidents; and that organizational safety climate and perceptions of supervisor enforcement of safety policies would moderate the relationship between unreported accidents and reported accidents. Results showed that the number of unreported accidents was significantly higher than the number of reported accidents. There was an average of 2.48 unreported accidents for every accident reported to the organization. Further, under-reporting was higher in working environments with poorer organizational safety climate or where supervisor safety enforcement was inconsistent. We discuss the implications of these findings for improving accident under-reporting and occupational safety in the workplace.     

Metal accumulation potential of wild plants in tannery effluent contaminated soil of Kasur, Pakistan: field trials for toxic metal cleanup using Suaeda fruticosa

The tannery effluent contaminated lands, adjacent to Depalpur Road, Kasur, Pakistan, have been rendered infertile due to long term effluent logging from the leather industry. The area has been colonized by twelve plant species among which Suaeda fruticosa, Salvadora oleoides and Calatropis procera have been found to be the most common and high biomass producing plants. S. fruticosa was subjected to further experimentation because of its high biomass and phytoextraction capabilities for metals. The pot and field experiments were carried out simultaneously. Pot experiments were conducted using the same field soil in column pots with stoppard bottoms to obtain the leachate. EDTA treatment caused a greater solubility of Cr in the soil pore water. In higher doses more amount of the heavy metal was leached. The increase in the amount of EDTA significantly caused a decrease in the biomass of plants without toxicity symptoms. A higher biomass of plants was observed in the field as compared to the pot experiment. The greatest amount of Na was accumulated by leaves of S. fruticosa followed by stem and roots. Similarly, the greatest amount of Cr was bioaccumulated by leaves of S. fruticosa, but followed by roots and then stem. S. fruticosa can be employed in rehabilitation of tannery effluent contaminated soil using small doses of EDTA.